I have a Starbucks Barista that I've used just about every single day for about ten years. A couple times the o-ring that creates the seal between the water feed and the boiler has started leaking. I've managed to successfully replace it each time. (Once I started using silicon instead of rubber o-rings the repairs started lasting a lot longer.) This time, unfortunately, I managed to strip either the bolt or the threads on the boiler--I'm not sure which until I do some more disassembly. I've searched online and have found a few places that sell parts for the machine, but none offer either of the parts I will need to replace. Does someone know of a place that has a more extensive selection of parts?

My Barista is leaking from the top of the boiler head, at the left rear nut (one of two nuts holding the heating element in place). I am hesitant to dig further into the boiler head without advice from this group. I removed that nut and found a lock washer and a metal plate (heat spreader?) underneath, but no visible O-ring or seal. My guess is the seal is on the underside, where the pressure is applied.

You mention using "silicone" instead of rubber O-rings as a more durable repair option. Do you mean on the underside (inside) of the heating element joint? It's tempting to run a bead of silicone sealant around the nut and retighten it, rather than dig further into disassembly. What is the most advisable next step from here?

You mention using "silicone" instead of rubber O-rings as a more durable repair option. Do you mean on the underside (inside) of the heating element joint? It's tempting to run a bead of silicone sealant around the nut and retighten it, rather than dig further into disassembly. What is the most advisable next step from here?

Ok, I have the boiler completely disassembled now. It was leaking around the nut labeled item 26 on page 2 of this diagram . But there is no replacable seal there. I could add an O-ring, or just put it back together and try tightening that nut, but it was pretty snug to start with.

Should that fitting have pressure on it from the underside? It’s the heating element, so I would think so. Item 46, the “filter holder gasket” has some gummy crud (coffee or melted rubber?) on the top, on the joint with item 40, “boiler, lower body.” I suppose I will clean it up and put it back together, looking closely for leaks now that I have “the lay of the land.”

Is it obvious to anyone what parts I need yet, if the leak is at item 26? Still tempted to put a bead of silicone sealer around the bottom of that joint, but I doubt the silicone would like the heat source, and may not be food-safe. Anyone?

Also, the wand leaked just a tad, before this big leak started, so I should fix that while I'm in here.

I do not have a machine to look at, but I think the nut 26 is for the element 37, and I believe that O-ring 51 goes on the element from the inside and seals off the element and nut 26. If that is correct, then the O-ring(s) is on the element or stuck to the boiler top. Silicone on the outside under the nut may not hurt, but should not be needed. If silicone is needed there, then the O-ring must be leaking and I doubt that silicone will hold for long in that case.

Happy ending: It turned out to be a cracked electrode on the heating element. I replaced the boiler O-ring (d2-38), the heating element (d2-37), the heating element O-rings (2 x d-51), and the filter holder gasket (d-46). I also adjusted the steam valve stop (as documented elsewhere on this forum), descaled the boiler with lemon juice while I had it disassembled, and cleaned off the crud that had melted onto the lower surface of the boiler, apparently from deterioration of the filter holder gasket (d-46).

When reassembling, be cautious of two details: 1. the steam wand micro switch (d2-18) has three connections on it: normally open, normally closed and common. Note the two that are used (normally open and common) and be sure to reconnect to the same terminals. Otherwise the pump motor will run when the steam valve is closed. It should run when the valve is opened. 2. Be sure the boiler O-ring (d2-38) is well seated as you tighten the four bolts holding the upper and lower boiler halves together. Mine blew out after reassembly, so I replaced the O-ring and coated it with a small amount of olive oil.

The machine is working perfectly now. You don’t really appreciate good espresso until you have to do without it for a few weeks. Could be my imagination, but I seem to be getting thicker creama with each cup now!! Stephano's rocks!

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